Transcript Air Toxics Rule Changes (pursuant to Session Law 2012-91) North Carolina Division of Air Quality July 2013 Environmental Management Commission.

Air Toxics Rule Changes
(pursuant to Session Law 2012-91)
North Carolina Division of Air Quality
July 2013 Environmental Management Commission
Acronyms
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AAL – acceptable ambient level
GACT – generally available control technology
MACT – maximum achievable control technology
SIC – standard industrial classification
TAP – toxic air pollutant
TPER – toxic permitting emission rate
Air Toxics – Summary of SL 2012-91
Section 1
◦ Exempts sources subject to certain federal regulations
◦ Codifies “Director’s Call” provision
Section 2
◦ Requires rule amendments
Section 3
◦ Requires review of rules and their implementation
Section 4
◦ Requires reports on implementation of this act
Air Toxics – Section 1
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Exempts from the State air toxics rules
sources of toxic air pollutants subject to
certain federal regulations, including:
 National Emission Standards for Hazardous Air Pollutants
(NESHAPs), 40 CFR Part 61
 Maximum Achievable Control Technology (MACT)
standards, 40 CFR Part 63
 Generally Available Control Technology (GACT) standards,
40 CFR Part 63
 Subject to case-by-case MACT, 112(j) of the Clean Air Act
Air Toxics – Section 1
When DAQ receives a permit application for a
new or modified source or facility that
would result in a net increase in toxic air
pollutants:
◦ Requires DAQ to determine if the toxic air emissions
would pose an unacceptable risk to human health… and
if it does, the Division Director would make a written
finding and require a permit application that eliminates
the unacceptable risk… (for all practical purposes this is
the existing Director’s Call provision)
Air Toxics – Section 3
Requires DAQ to review the State air toxics
rules and their implementation to determine
whether changes could:
◦ Reduce unnecessary regulatory burden
◦ Increase the efficient use of DAQ
resources while maintaining protection of
public health
 Conduct the review in consultation with
interested parties
 Report the results of the review and include
recommendations to the ERC by 12/1/12
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Recommendations for Rule
Changes
Develop an additional set of emissions
thresholds for pollutants coming from
unobstructed vertical stacks
2. Exempt natural gas and propane fired
boilers
3. Exempt emergency engines
4. Eliminate SIC call
5. Clarify use of actual rate of emissions
6. Remove the term “unadulterated wood”
from rules
1.
1. Develop additional toxic permitting
emission thresholds
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Develop an additional set of emissions
thresholds for pollutants coming from
unobstructed vertical stacks
◦ Additional thresholds approximately 1.3-4.8
times higher than current thresholds
◦ Health based standards stay the same.
1. Develop additional toxic permitting
emission thresholds
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TPERs calculated from AAL based on
dispersion modeling parameters
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AAL* (1/(Cmax * averaging time
factor)) * hours in averaging period
=TPER
1. Develop additional toxic permitting
emission thresholds
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Cmax is maximum emission rate
derived from dispersion model using
conservative input parameters
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Emission rate – 1 lb/hr
Physical stack height=5.0 meters
Stack gas temperature=293 degrees Kelvin
Stack gas velocity=1.0 m/s
Stack diameter=1.0 m
Resulting Cmax= 0.9497 grams/sec
Averaging Time Factor: Annual=0.1, Daily=0.6
2. Exempt natural gas and propane fired
combustion sources
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US EPA has exempted certain gas-fired
combustion units from federal air toxics
rules. Another federal rule only prescribes
work practice standards on affected units.
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Toxic air emissions from these sources are
well below the TPERs.
2. Exempt natural gas and propane fired
combustion sources
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Reviewed emissions profiles for all TAPs
from combustion of natural gas and
propane
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Using emissions estimation spreadsheets,
back calculated what heat input would
result in emission rate that would exceed
an existing TPER
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Result: Benzene was controlling pollutant
exceeding TPER at 450 million BTU/hr
3. Exempt emergency engines
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US EPA federal air toxics rules apply to all
emergency engines and only prescribe
work practice standards.
Used temporarily in emergency situations.
Small.
Few hours of operation.
Peak shaving engines are not considered
emergency engines.
3. Exempt emergency engines
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Reviewed emissions profiles for all TAPs
from combustion of diesel fuel in
emergency engines
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Using emissions estimation spreadsheets,
back calculated through iterative process
what size unit exceeds an existing TPER
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Result: Formaldehyde controlling pollutant
for hourly emissions at 4843 horsepower
4. Eliminate SIC call
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15A NCAC 02Q .0705 provides a
mechanism for the Director to require all
facilities under the same four-digit
Standard Industrial Classification (SIC) to
submit an application to comply with the
NC air toxics rules.
The existing Director’s Call rule and SL
2012-91 provide adequate authority to
address any unacceptable risks to human
health from any facility.
5. Clarify use of actual rate of emissions
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Clarify in the rule to ensure that DAQ is
implementing it consistently.
6. Remove term “unadulterated wood”
from rules
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Elimination of this term will prevent
confusion with definitions for combustion
sources in federal rules.
Additional Rule Changes
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Repeal 15A NCAC 02Q .0705, Existing
Facilities, due to elimination of last
MACT/GACT provision.
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Repeal of 15A NCAC 02Q .0714,
Wastewater Treatment Systems at Pulp
and Paper Mills, due to obsolete
requirements and implementation
schedules.
Asbestos AAL and TPER
Correction
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Calculation error in original
recommendation identified by SAB
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Old AAL = 2.8 x 10-11 fibers/mL
New AAL = the 2.8 x 10-6 fibers/mL
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Old TPER = 1.9 X 10-6 lb/year
New TPER = 5.7 x 10-3 lb/year
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No impact – no facilities in NC
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Impacts
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Average 94 permit applications per year
submitted to DAQ
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Section 1 - 34 facilities/year
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Recommendation 1 – 16 facilities/year
Recommendation 2 – 20 facilities/year
Recommendation 3 – 15 facilities/year
No impacts estimated for
recommendations 4, 5 and 6
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Fiscal Impacts
Reduced facility data collection costs
Reduced facility modeling costs
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$147,000 savings per year
Increased DAQ staff time due to
unacceptable risk determinations
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$6400 opportunity cost per year